Modular low pressure delivery vehicle air conditioning system

ABSTRACT

A modular air conditioning system comprises a self-contained refrigeration power cell, a heat exchanger remotely located from the refrigeration power cell, and a low pressure refrigerant communication circuit operably coupling the refrigeration power cell to the heat exchanger. The refrigeration power cell comprises a compressor, a condenser, an expansion device, and an evaporator which are serially coupled to form a high pressure closed refrigeration circuit. A drive mechanism, such as an electric or hydraulic motor, or conventional belt, is coupled to the compressor. The low pressure refrigerant communication circuit thermally interfaces with the condenser to remove heat from the high pressure closed refrigeration circuit. Alternatively, this circuit thermally interfaces with the evaporator to remove heat from the low pressure refrigerant. This heat exchanger is adapted to mount in the cabin of an over-the-road or off-road vehicle. Preferably, a second heat exchanger and a second low pressure refrigerant communication circuit is included. This second circuit thermally interfaces with the condenser to remove heat from the refrigeration circuit.

This application is a division of U.S. application Ser. No. 09/083,303filed May 22, 1998 now U.S. Pat. No. 6,038,877.

FIELD OF THE INVENTION

This invention relates to vehicle air conditioning systems, and moreparticularly to over-the-road or off-road or off-road vehicle airconditioning systems utilizing in-dash delivery of air conditioned air.

BACKGROUND OF THE INVENTION

Over-the-road or off-road vehicles, such as semi-tractor trailers andconstruction vehicles, are increasingly utilized to satisfy thetransportation and construction needs of our economy. These increasedneeds result in increased utilization of these vehicles to the pointwhere many are operated seven days a week and upwards of eighteen (18)to twenty (20) hours a day with a two person crew or multiple shiftoperations. This increased utilization is not simply a vehiclestatement, but also includes a human factor as these vehicles areoperated by at least a driver and often times by a driving teamconsisting of two individuals who share the duty of operating thevehicle. Since these vehicles are operated so extensively, increaseddriver and passenger comfort is essential, both in terms of environmenttemperature and physical space within the vehicle cab. The need forenvironmental comfort during warm weather is satisfied through the useof an over-the-road or off-road vehicle air conditioning system, whilethe physical layout has been accommodated through new ergonomic interiordesigns, including reduced dash size, to maximize the available roomwithin the vehicle cab for passenger occupation.

Typical over-the-road or off-road vehicle air conditioning systems areof the compressor type. These air conditioning systems utilize acompressor, which is driven by a belt coupled to the engine to compressa refrigerant vapor under high pressure which is then circulated througha condenser to remove heat from the compressed high pressure vapor andchange it to a liquid state. The liquid refrigerant is then passedthrough an expansion valve which reduces the pressure on the refrigerantsomewhat. This lower pressure refrigerant is then passed through anevaporator, which permits the return of the refrigerant to the vaporstate, thereby removing heat from the air blown thereacross by anin-dash fan.

In a modern over-the-road or off-road vehicle, the main components ofthe refrigeration system, including the compressor and the condenser,are located remotely from the evaporator which is typically installedbehind the dashboard air vents to provide cooling of the cabin air asdescribed above, and from the condenser which is typically mounted withthe vehicle radiator in the front of the engine compartment. Since thetypical compressor vehicle air conditioning system is a closed loopsystem, the circulating high pressure refrigerant must be passed fromthe remotely located components within the engine compartment to thevehicle cab-located evaporator and to the forward engine compartment,radiator located condenser via expensive high pressure refrigerationhoses. A typical installation includes the compressor and condenser inthe engine compartment of the over-the-road or off-road vehicle, andutilizes multiple high pressure refrigeration lines to couple thesecomponents through the firewall and into the cab behind the dash to thelocation of the evaporator, and to the radiator area of the enginecompartment. Each of these high pressure refrigeration lines requirehigh pressure couplings at each connection for the delivery and returnof the high pressure refrigerant in the air conditioning system.

As can well be imagined, both from the above-description as well as frompersonal experiences with vehicular air conditioning systems, thistypical installation arrangement for an over-the-road or off-roadvehicle air conditioning system is severely prone to leaks of the highpressure refrigerant. These leaks occur at various locations, but aremost frequent at the various couplings of the high pressure hose whichroutes the high pressure refrigerant from the condenser to the interiorof the cab, under the dash, and to the location of the evaporator.Another frequent area for leaks occurs at the various couplings of thehigh pressure hose which routes the high pressure refrigerant from thecompressor to the radiator area located condenser. These leaks result ina reduced efficiency of the air conditioning system, expensiverecharging of the system with new refrigerant, as well as a hazard tothe environment through the escape of the refrigerant. An increasedconsciousness of the environmental impact that escaped refrigerant hason the planet, as well as increased government regulation regarding theinadvertent release of refrigeration refrigerant, has placed anincreased emphasis on overcoming these problems.

In addition to the problem of leaks within the air conditioning system,the use of this type of system requires that expensive high pressurerefrigeration lines be utilized within the engine compartment, andbetween the engine compartment and the interior of the cab. In addition,expensive high pressure couplings must also be utilized in an attempt toreduce the potential for leaks and catastrophic failure of the airconditioning system due to a failed connection of the high pressurerefrigeration lines. Also, because the refrigeration system is notclosed until assembly of the vehicle takes place within themanufacturing assembly facility, the use of this type of system furtherburdens the assembly manufacturer by requiring that the initial purgingand charging of the refrigeration system take place within the assemblyplant of the vehicle itself. As mentioned above, since the use ofrefrigerant is a highly regulated process, requiring the manufacturingassembler to charge the refrigeration system greatly increases the costassociated with the manufacture of the vehicle.

In an attempt to overcome many of the above-mentioned problems, severalmanufacturers of over-the-road or off-road vehicle air conditioningsystems have designed self-contained systems which include not only thecompressor and condenser, but also the evaporator within a closeproximity to one another thereby reducing the potential sources ofrefrigerant leak. However, such systems require a large dedicated blockof space be set aside for the refrigeration system within, or withinvery close proximity to, the cab of the over-the-road or off-roadvehicle. One such system is illustrated by U.S. Pat. No. 5,222,372issued to Derees, et al. on Jun. 29, 1993 for a MODULAR VEHICLE AIRCONDITIONING/HEATER ASSEMBLY. This patent describes the modular airconditioning assembly as being contained in a housing enclosure which iscarried by the vehicle in a recess formed by the interior body panel ofthe vehicle which separates the engine compartment from the passengercompartment, under the dashboard of the vehicle. However, while such asystem may be feasible in a passenger vehicle having a large dashboard,such a system is currently not feasible for an over-the-road or off-roadvehicle as there is not enough space under the dash for installation ofsuch a large unit.

Other systems, in an attempt to reduce the distance between the maincomponents of the air conditioning system and the evaporator, have goneto a roof mounted design, such as that described in U.S. Pat. No.4,217,764 issued to Armbruster on Aug. 19, 1980 for a ROOF MOUNTED MOTORVEHICLE AIR CONDITIONER. However, these roof-mounted systems aretypically quite bulky, and require that a hole be cut into the roof ofthe vehicle to accommodate the cold air vents. As these systems mount onthe roof of the vehicle, they also significantly increase the amount ofwind drag over the vehicle. In an effort to reduce this drag, a cowlingis often included which also increases the cost of the system.Additionally, the air vents which protrude down from the roof of thevehicle significantly impact the ergonomic design of the cab by reducinginterior passenger occupation space, as well as increasing the potentialof head injury. Additionally, the increased vibration and noise whichmay result from operating the refrigeration system directly above thehead of the driver and occupant of the over-the-road or off-road vehiclefurther reduces the desirability of this type of system.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to overcome many of these andother problems existing in the art. More specifically, it is an objectof the instant invention to provide an over-the-road or off-road vehicleair conditioning system which has increased reliability and decreasedimpact to the environment. It is an additional object of the instantinvention to provide an over-the-road or off-road vehicle airconditioning system which eliminates the necessity for evacuating andcharging of the air conditioning system at the manufacturing assemblyplant. Further, it is an object of the instant invention to provide anover-the-road or off-road vehicle air conditioning system which utilizesan in-dash heat exchange with the cab air while eliminating thenecessity for high pressure refrigeration lines and high pressurecouplings running to and from the cab compartment. It is an additionalobject of the instant invention to provide an over-the-road or off-roadvehicle air conditioning system which is modular in design, allowing forremote location of the main refrigeration circuit. It is an additionalobject of the instant invention to provide an over-the-road or off-roadvehicle air conditioning system which allows for location of the mainair conditioning circuit outside of the engine compartment in other moreconvenient locations.

In view of these and other objects of the invention, it is a feature ofthe instant invention to provide an air conditioning system whichutilizes a self-contained refrigeration system which is remotely locatedfrom the in-dash heat exchanger for the cabin air. It is a furtherfeature of the instant invention that the remotely locatedself-contained portion of the air conditioning system contains all ofthe high pressure system components in a closed system having permanentconnections therebetween. It is an additional feature of the instantinvention that the in-dash heat exchanger located within the cabin ofthe over-the-road or off-road vehicle contain a low pressure refrigerantcircuit which is utilized to cool the cabin air. It is a further featureof the instant invention that the low pressure refrigerant circuitinterfaces with the high pressure, remotely located refrigerant systemvia a heat exchanger. Further, it is a feature of the instant inventionthat the air conditioning system also utilizes a low pressurerefrigerant circuit to remove heat from the compressed refrigerant inthe high pressure, remotely located self-contained modular circuit.

In view of the above, an embodiment of the air conditioning system foran over-the-road or off-road vehicle having an engine located in anengine compartment and an occupant cabin, the occupant cabin having adashboard including air flow vents and a vent fan included, the systemof the present invention comprises a refrigeration power cell, a firstheat exchanger adapted to be mounted in the dashboard of the occupantcabin, and a first low pressure refrigerant communication circuitoperably coupling the first heat exchanger to the refrigeration powercell.

In this system the refrigeration power cell comprises a high pressurecondenser-based refrigeration circuit. This circuit has a compressor, acondenser, an expansion device, and an evaporator. Also included is acirculation circuit which supplies low pressure refrigerant to the lowpressure refrigerant communication circuit. The evaporator and thecirculation circuit are in thermal communications whereby heat isremoved from the low pressure refrigerant. Preferably, the circulationcircuit comprises a low pressure refrigerant pump and an input andoutput low pressure refrigerant coupling. This pump circulates the lowpressure refrigerant through this heat exchanger across which the ventfan blows air to be cooled. This produces cooled air which flows throughthe vents and into the occupant cabin to cool same.

Preferably, the system of the present invention further comprises asecond heat exchanger adapted to be mounted in the engine compartment,and a second low pressure refrigerant communication circuit operablycoupling this second heat exchanger to the refrigeration power cell.Additionally, the refrigeration power cell further comprises a secondcirculation circuit supplying a second low pressure refrigerant to thissecond low pressure refrigerant communication circuit. The condenser andthis second circulation means are preferably in thermal communicationswhereby heat is removed from the refrigeration power cell by the secondlow pressure refrigerant. In a system wherein the engine includes aradiator and an engine fan within the engine compartment, this secondlow pressure refrigerant circulates through the second heat exchangeracross which the engine fan draws air to remove heat from this secondheat exchanger thereby cooling the second low pressure refrigerant.

In an embodiment of the instant invention, the refrigeration power cellfurther comprises a sub-cooler thermally coupling the low temperatureinput of the compressor to the high temperature output of thecompressor. This heat exchange increases the efficiency of thecompressor. Additionally, the refrigeration power cell further comprisesa drier interposed between the condenser and the expansion device. Thisdrier removes water from the refrigeration circuit.

In an alternate embodiment of the instant invention, a modular airconditioning system comprises a self-contained refrigeration power cell,a heat exchanger remotely located from the refrigeration power cell, anda low pressure refrigerant communication circuit. This low pressurerefrigerant communication circuit operably couples the refrigerationpower cell to the heat exchanger, conveying low pressure refrigeranttherebetween. The refrigeration power cell comprises a compressor, acondenser, an expansion device, and an evaporator. The compressor,condenser, expansion device, and evaporator are serially coupled to forma high pressure closed refrigeration circuit.

The refrigeration power cell further comprises a drive mechanism coupledto the compressor. This drive mechanism may be a hydraulic motor, anelectric motor, or other appropriate device to allow remote operationfrom the engine compartment. Alternatively, the compressor may be beltdriven in a conventional manner.

In an embodiment of the instant invention, the low pressure refrigerantcommunication circuit thermally interfaces with the condenser to removeheat from the high pressure closed refrigeration circuit. In thisembodiment this heat exchanger is adapted to mount in proximity to aradiator in an engine compartment of an over-the-road or off-roadvehicle.

Alternatively, the low pressure refrigerant communication circuitthermally interfaces with the evaporator to remove heat from the lowpressure refrigerant. In this alternative embodiment the heat exchangeris adapted to mount under a dashboard of an over-the-road or off-roadvehicle. Preferably, this embodiment of the instant invention furthercomprises a second heat exchanger remotely located from therefrigeration power cell, and a second low pressure refrigerantcommunication circuit which is operably coupled to the refrigerationpower cell and to the second heat exchanger for conveying second lowpressure refrigerant therebetween. In this embodiment the second lowpressure refrigerant communication circuit thermally interfaces with thecondenser to remove heat from the high pressure closed refrigerationcircuit. Ideally, this second heat exchanger is adapted to mount inproximity to a radiator in an engine compartment of an over-the-road oroff-road vehicle.

These and other objects and advantages of the invention will become moreapparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system block diagram illustrating an embodiment of theinstant invention;

FIG. 2 is an expanded system block diagram of the embodiment of theinstant invention illustrated in FIG. 1;

FIG. 3 is a system block diagram illustrating an alternate embodiment ofthe instant invention;

FIG. 4 is an expanded system block diagram of the alternate embodimentof the instant invention illustrated in FIG. 3;

FIG. 5 is a system block diagram illustrating a further alternateembodiment of the instant invention; and

FIG. 6 is an expanded system block diagram of the further alternateembodiment of the instant invention illustrated in FIG. 5.

While the invention is susceptible of various modifications andalternative constructions, certain illustrative embodiments thereof havebeen shown in the drawings and will be described below in detail. Itshould be understood, however, that there is no intention to limit theinvention to the specific forms disclosed, but on the contrary, theintention is to cover all modifications, alternative constructions andequivalents falling within the spirit and scope of the invention asdefined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In a preferred embodiment of the instant invention as illustrated inFIG. 1, a modular low pressure delivery vehicle air conditioning systemcomprises a refrigeration power cell 10 which may be located anywhereroom allows within or without the over-the-road or off-road vehicle.This refrigeration power cell 10 is a modular self-contained unit andcomprises a high pressure refrigeration circuit having permanentconnections between components as will be described more fullyhereinbelow. In a preferred embodiment of the instant invention, thelevel of modularization of the system is total and includes an in-dashheat exchange unit 12 and a radiator mounted heat exchanger 14. Each ofthese heat exchangers 12, 14 are in thermal communication with therefrigeration power cell by low pressure refrigerant communication means16, 18.

As described above, an over-the-road or off-road vehicle includes anoccupant cabin for the driver and passenger to sit, and possibly anoccupant sleeper cabin which provides a bunk area for the driver oroccupant to sleep while not driving the vehicle. As is conventional, theoccupant cabin includes a dashboard having, among other things, airvents located therein. Typically, a vent fan is included behind thedashboard to force air through the dash mounted vents into the occupantcabin. In a preferred embodiment of the instant invention, the in-dashheat exchanger 12 is configured or adapted to mount behind the dashboardwithin the occupant cabin. The operation of this in-dash mounted heatexchanger will be described more fully below with reference to FIG. 2.

Also as described briefly above, an over-the-road or off-road vehicleincludes an engine compartment which typically houses the vehicle's maindrive engine as well as other accessory components. One such accessorycomponent is the vehicle's radiator through which engine refrigeranttypically circulates to remove heat from the vehicle's engine.Typically, an engine fan is also included behind the radiator to drawair thereacross to aid in the heat removal process, especially when thevehicle is not moving. In a preferred embodiment of the instantinvention, the radiator mounted heat exchanger 14 is configured oradapted to allow mounting on or in proximity to the radiator such thatair which enters the engine compartment or which is drawn therein by theengine fan will flow across this heat exchanger 14 to also remove heattherefrom. A further description of the operation of this heat exchangerwill be made with reference to FIG. 2.

As described above with regard to the background of the invention, oneof the problems existing in the art pertains to the physical spacerequirements of an air conditioning system if placed within the enginecompartment of an over-the-road or off-road vehicle. These enginecompartments are typically quite crowded with the engine and accessorycomponents which are required to be located in this same area. However,with the embodiment of the instant invention as illustrated in FIG. 1,the refrigeration power cell 10 is a self-contained, closed, modularunit which may be located remotely from the engine compartment, mountedwithin the vehicle or externally thereto.

However, as described above, one of the problems associated withdistributing the components of the air conditioning system from thein-dash delivery of cooled air is that the high pressure refrigeranttypically leaks from the system at the various high pressure couplingsrequired to route this high pressure refrigerant to the various requiredareas within the vehicle. The instant invention obviates this problem byutilizing low pressure refrigerant which is circulated to the heatexchangers 12, 14 by a low pressure refrigerant communication circuits16, 18 respectively. These low pressure refrigerant communicationcircuits 16, 18 are in thermal communication with the high pressurerefrigeration power cell 10 but do not suffer from the same highpressure refrigerant leak problem as a typical system. In this way, therefrigeration power cell 10 is able to be located in any convenientremote location on or in the vehicle without concern for the number ofcouplings required to place the heat exchangers 12, 14 in theirpreferred locations.

FIG. 2 illustrates in greater detail the embodiment of the instantinvention illustrated in simplified block diagrammatic form in FIG. 1.As may be seen from FIG. 2, the refrigeration power cell 10 comprises ahigh pressure condenser based refrigeration circuit having a compressor20, a condenser 22, an expansion device 24, and an evaporator 26. Thesecomponents operate to form a high pressure closed refrigeration circuit,the specific operation of which is well known in the art.

However, unlike prior high pressure refrigeration systems, thecomponents of the refrigeration power cell 10 are coupled by fixedtubing having permanent connections, such as soldered, braised, etc.,connections, as opposed to releasable connectors which are typical inprior systems. This fixed tubing and permanent connections allow for therefrigeration power cell 10 to be a highly reliable essentially leakproof system which does not suffer from the problems of prior vehicleair conditioning systems of allowing high pressure refrigerant to leakthrough the various removable connections between components.Preferably, this refrigeration power cell will be a prepackaged andpre-charged unit which may be installed in the vehicle without concernfor evacuating and charging of the air conditioning system at themanufacturing assembly facility of the vehicle as is common with priorsystems.

The refrigeration power cell 10 may also include, in the high pressurerefrigeration circuit, a sub-cooler 28 which thermally associates thelow temperature input to the compressor containing vaporized refrigerantwith the high temperature compressor output containing high temperaturecompressed refrigerant. In this way, the efficiency of the compressor isgreatly increased as the high temperature liquid refrigerant in thecompressor output is used to heat the refrigerant vapor flowing into thecompressor, while at the same time the low temperature vapor in thecompressor input is used to cool the compressed refrigerant flowing tothe condenser. Additionally, a conventional dryer 30 may be included inthe high pressure refrigeration circuit of the refrigeration power cell10 to remove water from the circuit. While the use of such a dryer 30 istypically not needed in a totally closed high pressure refrigerationcircuit, if the compressor 20 utilized in the circuit includes a seal,the use of the dryer 30 is preferred.

Unlike a conventional high pressure refrigeration circuit which placesthe condenser 22 in proximity to the radiator of the vehicle to removeheat from the high pressure refrigeration circuit, the condenser 22 ofthe instant invention is not positioned remotely from the othercomponents of the refrigeration power cell 10. Instead, the condenser 22of this embodiment of the instant invention serves as a heat exchangerbetween the high pressure refrigeration circuit 32 and the low pressurerefrigerant circuit 18 which circulates low pressure refrigerant to aradiator mounted heat exchanger 14. In this way, heat generated by thehigh pressure refrigeration circuit 32 is removed to the low pressurerefrigerant circuit 18 and circulated to the radiator mounted heatexchanger 14. As the engine fan 34 operates, air is drawn across theheat exchanger 14 thereby removing heat from the low pressurerefrigerant circulating therethrough. As is conventional, the fan neednot operate while the vehicle is traveling, as normal air flow throughthe engine compartment may serve to remove sufficient heat from the heatexchanger 14 to obviate the necessity of running the engine fan 34.

The means 18 for this low pressure refrigerant communication may utilizesimple, inexpensive, insulated tubing such as that utilized for a lowpressure heating system. To coordinate with the low pressure refrigerantcommunication means 18, the refrigeration power cell 10 includes a lowpressure refrigerant circulation means which includes the low pressurecouplings to interface with the low pressure tubing, as well as a lowpressure refrigerant pump 36. This pump 36 is utilized to circulate thelow pressure refrigerant through the low pressure circuit which includesthe heat exchanger 14 and the condenser heat exchanger 22. As will berecognized by one skilled in the art, while the heat exchanger 14 hasbeen described in a radiator mount configuration, the heat exchanger 14may actually be mounted in any convenient location having sufficient airflow to remove heat from the heat exchanger 14.

The high pressure refrigeration refrigerant circuit 32 of therefrigeration power cell 10 also deviates from a typical high pressurerefrigeration circuit by utilizing its evaporator 26 to cool the lowpressure refrigerant circuit 16 as opposed to directly cooling the airin the cabin. Instead, the high pressure refrigeration circuit 32 of theinstant invention is utilized as a heat exchanger which extracts heatfrom the low pressure refrigerant circulating in the circuit 16. As withthe configuration described above, the refrigeration power cell 10includes a low pressure refrigerant circulation means including lowpressure fittings and a low pressure refrigerant pump 36 whichcirculates the low pressure refrigerant through the low pressurecommunication circuit 16, the heat exchanger 12, and the evaporator heatexchanger 26.

Unlike a conventional system which utilizes a dashboard mountedevaporator, the system of the instant invention utilizes the evaporator26 to serve as a heat exchanger cooling the low pressure refrigerantcirculating therethrough. As this low pressure refrigerant is circulatedthrough the low pressure tubing to the in-dash mounted heat exchanger12, the vent fan 40 blows air thereacross, through the air vents locatedin the dashboard, and into the occupant cabin to cool the air therein.Since this system is circulating low pressure refrigerant, the distanceand number of couplings from the refrigeration power cell 10 to thedashboard of the vehicle is not a concern, unlike systems which attemptto circulate high pressure refrigerant as is typical.

The operation of the compressor 20 in the refrigeration power cell 10may be driven by a suitable drive means 42 which is included as part ofthe refrigeration power cell 10. In this way, the refrigeration powercell 10 may be a totally self-contained modular unit capable of beinglocated anywhere within or outside of the vehicle. Devices which may beutilized to drive the compressor 20 include electric or hydraulicmotors, or other appropriate drive mechanisms. If the refrigerationpower cell is to be located within the engine compartment, or inproximity to other rotating elements, a shaft or belt drive may beutilized as appropriate and desired.

As will be recognized by one skilled in the art, the use of theself-contained refrigeration power cell 10 eliminates the need forseparate refrigeration hoses or tubing, thereby reducing the cost of themanufacture of this system. The absence of hoses and their requiredconnections also greatly reduces the possibility of refrigeration leaksin the high pressure refrigeration circuit 32, thereby reducing the costof ownership and providing enhanced benefits to the environment. Sincethe components are located in close proximity to one another within therefrigeration power cell 10, the system is inherently more efficient andutilizes a reduced volume of refrigerant, once again reducing the costof the system. Since this unit is modular, it is easy to install withinthe vehicle which reduces the cost of manufacturing the vehicle.Additionally, since the refrigeration power cell 10 is a self-containedunit, it may be delivered to the vehicle assembly plant fully chargedwith refrigerant, thereby obviating the need for evacuation or chargingduring the installation of the unit within the vehicle. This not onlygreatly reduces the cost of manufacturing of the vehicle, but alsorelieves the assembly plant from various government regulations whichgovern the handling and installation of refrigerant.

An alternate embodiment of the instant invention is illustrated in FIG.3. As may be seen with reference to this FIG. 3, the refrigeration powercell 10 interfaces solely with an in-dash heat exchanger 12 via a lowpressure refrigerant communication circuit 16. In this embodiment of theinstant invention, the need for a separate low pressure circuit and heatexchanger 14 (see FIG. 1) is obviated by the location of therefrigeration power cell 10 within the vehicle. Particularly, if therefrigeration power cell is located in an area which receives sufficientairflow to cool the high pressure refrigeration circuit 32 (see FIG. 4)then a separate low pressure refrigerant circuit to perform thisfunction is not required.

With specific reference to FIG. 4, this embodiment of the instantinvention utilizes the condenser 22 in a more conventional fashion as adirect heat exchange element for the high pressure refrigeration circuit32. This configuration may be appropriate where, for example, therefrigeration power cell 10 is located within the engine compartment andmay utilize the airflow generated by the movement of the vehicle and/orthe engine fan 34. Alternatively, this configuration may be appropriatewhen the refrigeration power cell 10 is located externally to thevehicle in a location which receives sufficient airflow across thecondenser 22 to provide adequate heat removal from the high pressurerefrigeration circuit 32. The inclusion of a fan to aid air flow may beappropriate to enhance performance.

Alternatively, as illustrated in FIG. 5, the location and configurationof the refrigeration power cell 10 may obviate the need for a separatein-dash heat exchanger 12 (see FIGS. 1 and 3), and may only need toutilize a separate remotely located heat exchanger 14 to cool the highpressure refrigeration circuit 32 (see FIG. 6). This particularconfiguration, as illustrated in greater detail in FIG. 6, utilizes theevaporator 26 of the high pressure refrigeration circuit 32 in a moreconventional manner by providing direct heat exchange to the cabin airas delivered by the vent fan 40. Such a configuration is appropriatewhen the refrigeration power cell is configured to mount within thevehicle's occupant cabin so that direct heat exchange to the cabin airis appropriate across the evaporator 26. In such a configuration, theheat generated by the high pressure refrigeration circuit must still beremoved through the condenser by the low pressure refrigerant circuit 18to the remotely located heat exchanger 14 described above. As will berecognized by one skilled in the art, while the heat exchanger 14 hasbeen described with regard to a proximity mounting with the engineradiator, one skilled in the art will recognize that any remote locationof this heat exchanger 14 in an area having sufficient air flow toaccomplish the requisite heat removal from the system is appropriate.Likewise, one skilled in the art will also recognize that the referenceto in-dash mounted heat exchangers, while a conventional configurationfor an air conditioning system within an over-the-d or off-road vehicle,is not limiting as alternate configurations such as floor or ceilingmounted vents are also appropriate and included within the scope of theinstant invention.

Numerous modifications and alternative embodiments of the invention willbe apparent to those skilled in the art in view of the foregoingdescription. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the best mode for carrying out the invention. The details of thestructure and architecture may be varied substantially without departingfrom the spirit of the invention, and the exclusive use of allmodifications which come within the scope of the appended claims isreserved.

What is claimed is:
 1. An air conditioning system for an over-the-roador off-road vehicle having an engine located in an engine compartmentand an occupant cabin, the occupant cabin having a dashboard includingair flow vents and a vent fan included therein, the system comprising: arefrigeration power cell including a high pressure condenser-basedrefrigeration circuit having a compressor, condenser, expansion device,and evaporator serially coupled by fixed tubing having permanentconnections; a first heat exchanger adapted to be mounted in thedashboard of the occupant cabin; and low pressure refrigerantcommunication tubing for operably coupling said first heat exchanger tosaid refrigeration power cell.
 2. The system of claim 1, wherein saidrefrigeration power cell further comprises: a low pressure circulationpump for supplying low pressure refrigerant to said low pressurerefrigerant communication tubing; and wherein said evaporator and saidcirculation pump are in thermal communications whereby heat is removedfrom the first low pressure refrigerant.
 3. The system of claim 2,wherein said evaporator and said circulation pump are coupled by fixedlow pressure tubing having permanent connections.
 4. The system of claim1, wherein said refrigeration power cell is located completely in theengine compartment.
 5. The system of claim 4, wherein the enginecompartment and the occupant cabin are separated by a firewall, thesystem further comprising low pressure couplings penetrating thefirewall and interposed in said low pressure refrigerant communicationtubing to facilitate penetration of the firewall thereby.
 6. The systemof claim 4, wherein said refrigeration power cell is fully charged withhigh pressure refrigerant prior to location thereof in said enginecompartment.
 7. The system of claim 4, wherein said refrigeration powercell is located in operable proximity to an engine fan to remove heatfrom said refrigeration power cell.
 8. A modular air conditioningsystem, comprising: a self-contained refrigeration power cell includinga high pressure compressor and an evaporator coupled in series by fixedtubing having permanent connections; a first heat exchanger remotelylocated from said refrigeration power cell; and a low pressurerefrigerant communication circuit operably coupled to said refrigerationpower cell and to said first heat exchanger, said low pressurerefrigerant communication circuit adapted to convey low pressurerefrigerant therebetween.
 9. The system of claim 8, wherein saidrefrigeration power cell further comprises: a condenser; and anexpansion device; and wherein said compressor, condenser, expansiondevice, and evaporator are serially coupled by said fixed tubing havingpermanent connections to form a high pressure closed refrigerationcircuit.
 10. The system of claim 9, wherein said compressor is adaptedto be driven by a hydraulic motor or an electric motor.
 11. The systemof claim 9, wherein said low pressure refrigerant communication circuitthermally interfaces with said evaporator via a removable connection toremove heat from the first low pressure refrigerant, and wherein saidfirst heat exchanger is adapted to mount under a dashboard of a vehicle.12. The system of claim 8, wherein said refrigeration power cell islocated completely in an engine compartment of a vehicle and said. 13.The system of claim 12, wherein the engine compartment and an occupantcabin of the vehicle are separated by a firewall, the system furthercomprising low pressure couplings penetrating the firewall andinterposed in said low pressure refrigerant communication tubing tofacilitate penetration of the firewall thereby.
 14. An air conditioningsystem for an over-the-road or off-road vehicle, comprising: a highpressure refrigeration power cell utilizing fixed high pressure tubing;and at least one low pressure refrigeration circuit in removable thermalcommunication with said high pressure refrigeration power cell, said lowpressure refrigeration circuit including a heat exchanger fortransmitting thermal energy communicated from said high pressurerefrigeration power cell.
 15. The system of claim 14, wherein said highpressure refrigeration power cell comprises: a compressor; an evaporatora condenser; and an expansion device; and wherein said compressor,evaporator, condenser, and expansion device are coupled in series bysaid fixed high pressure tubing utilizing permanent connections.
 16. Thesystem of claim 14, wherein said high pressure refrigeration power cellis located within an engine compartment of the over-the-road or off-roadvehicle.
 17. The system of claim 16, wherein said high pressurerefrigeration power cell is fully charged with high pressure refrigerantprior to being located in the engine compartment.